Safety device for rock drills



April 25, 1933. E. L 1,905,474-

SAFETY DEVICE FOR ROCK DRILLS Filed May 15, -l93l VW/ 1y: 7 7

INVEN TOR.

HIS ATTORNEY.

Patented Apr. 25, 1933 UNITED STATES PATENT orrlcr:

EARL IB. LEAR, OF PHILLIPSBUBG, NEW JERSEY, ASSIGNOR TO INGERSOLL-RAND COM- PANY, OF JERSEY CITY, NEW JERSEY, .A CORPORATION OF NEW JERSEY sArE'rY mwrca r012. ROCK DRILLS Application filed May 15, 1931. Serial No. 537,597. I

This invention relates to rock drills, but more particularly to a safety dev1ce for fluld actuated rock drills, as for instance of the stoper ty e having rotation mechanism for a rotating t e working implement in the drill hole and in which the hammer piston of the drill and a rifle bar interlockingly engaged thereby serve as instrumentalitles for rotating the working implement.

One object of the invention is to enable the rotation mechanism to be rendered mstantly inefi'ective to change the position of the working implement in the drill hole.

Another object is to automatically disconnect the rotation mechanism from the comparatively stationary element of the rock drill and which elements may serve as holding devices or abutments for the rotation mechanism.

Still another object is to prevent rotation of a stoper type rock drill about the drill steel on such occasions as when the drill steel becomes stuck in the drill hole or unduly resists the action of the rotation mechanism.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying this specification and forming a part thereof and in which similar reference characters refer to similar parts,

Figure 1 is a sectional elevation of so much of a rock drill as will serve to illustrate the invention and a practical application thereof,

Figure 2 is a transverse view taken through Figure 1 on the line 2-2 looking in the direction indicated by the arrows,

lgigure 3 is a perspective view of a pawl an Figure 4 is a view similar to Figure 2 taken through Figure 1 on the line 4-4 lookingtin the direction indicated by the arrows.

eferring to the drawing in which is shown an intermediate portion of a rock drill of the stoper type, A and B designate the percussive and feeding elements respectively of the drill.

The percussive element comprises the usual cylinder C having a piston chamber D wherein is arranged a reciprocatory hammer piston E for actuating the working 1mplement (not shown) but'which may extend into and be interlocked with suitable chuck mechanism (not shown). The chuck mechanism may, in turn, be conveniently interlocked with the hammer piston E in a manner well known to efi'ect rotary movement of the working implement inaccordance with the degree of rotative movement of the hammer piston.

The pressure fluid utilized for actuating the piston E may be distributed to the plston chamber D by a distributing valve such as that designated by F and arranged withina valve chamber G formed in this instance in a pair of cooperating plates H and J at the rear end of the cylinder 0. The plate J, in the arrangement shown, is disposed between the cylinder C and the plate H and forms a closure for the rear end of the piston chamber D. The rear end of the plate J serves as a seating surface K for the wings L and O of the valve F.

The wing O of the valve in this instance controls the admission of pressure fluid to the rear end of the piston chamber D through a rear inlet passage P in the plate J The wing L controls the flow of pressure fluid from the valve chamber G through a front inlet passage Q located in the plate J and in the cylinder C to convey pressure fluid to the front end of the piston chamber.

The rotation mechanism employed for imparting rotary movement to the piston E comprises a ratchet ring R seated on the plate H and having a bore S to receive thehead T of a rifle bar U which extends into the piston chamber D to interlockingly engage the hammer piston E in a well known manner. Disposed in the head T to oscillate therein are pawls V, two being shown in the present instance, and said pawls are adapted to engage teeth W in the ratchet ring R. The pawls V may be provided with the usual springs X disposed in recesses Y in the head T and pressing against the pawls V for actuating said pawls into engagement with the teeth W.

Disposed on the rear end of the rotation ratchet is a back head Z upon which is seated a head block I) having arranged therein a throttle valve which may be of the rotary t lype and has a'lever d for its manipulation.

he throttle valve 0 may be rovided with a central passage e into whic pressure fluid 8 may be constantly introduced from a suitable source of supply.

The feeding element for advancing the rock drill towards the work in accordance with the penetration of the working implement 1 into the work comprises the usual feeding cylinder f which may be'seated against the head block b and clamped rigidly thereto b the usual side bolts (not shown) but whic ma also serve to clam the other casing parts, suc as the cylinder the plates J and H the ratchet rin R, the back head Z and the head .block together. In the feeding cylinder f isdisposed a feed piston g of a well known type and which may be provided with a rod h carrying at its lower or outermost end a pointer (not shown) but which may be adapted to seat upon a mine floor to support the drillin mechanism. The feedin cylinder f and t e piston 9 may be of any we own construction in which the piston g and the feeding cylinder f are freely rotatable with respect to each other.

In order to maintain a suitable pressure within the feeding cylinder f to act against the feeding iston g for elevating or extendis provided with a supply passage 7' which opens into the feeding c linder f with. one end. The other end of t e passage 1' is controlled by the throttle valve 0 which is provided with a port In through which pressure fluid ma flow from the passa e e into the passage y. The port k may, in t e open position of the throttle valve 0, register with a supply assage 0 which leads from the chamber w erein the throttle valve 0 is arranged to the valve chamber G to convey pressure fluid into the said valve chamber G for distribution by the valve F.

In accordance with the practice of the invention, means are provided for selectively retaining the pawls V out of engagement from the teeth W when, due to breakage or other causes, the workin implement tends to stick in the drill hole. enever this occurs and in the absence of suitable releasing means, the casing parts will rotate about the drill steel. This is objectionable, particularly in drilling mechanisms, such asvthose of the stoper type, having a rotation handle as that designated by g with an associated grip member 1' adapted to be grasped by the operator to prevent rotation' of the casing elements and against which the rotation mechanism reacts.

It is accordingly contemplated to render the rotation mechanism ineffective for its normal function immediately upon release of the operators grip on the rotation handle q. To this end the pawls V are pro- 06 vided with cam s rfaces which p eferab y ing the driliing apparatus the head block b merge at one end into the surface of the trunnicns t of the pawls V. The surfaces 8 may be slightly curved and extend diagonally across the rear end of the pawls and lie within a chamber u defined by an annular flange vcarried by the back head Z and extending into the ratchet ring R.

The back head Z in this instance is provided with a bore w into which extends an extension a: of the head block b and of somewhat smaller diameter than the bore w to form therebetween a chamber 3 for the reception of a plunger in the form of a sleeve 2. In the extension :1! is a bore 2 to receive a trunnion 3 of the rifle bar U.

The chamber u, which opens into the front end of the bore w, is of smaller diameter than the bore and extendinginto said chamber u is areduced flan e 4 of the sleeve '2. The flange 4 is provid at its free end with an inclined surface 5 which is adapted to cooperate with the cam surfaces 8 for rocking the pawls V and for holding the said pawls out of engagement from the teeth W.

The sleeve 2 is adapted to be actuated and held in its limiting positions by pressure fluid. This sleeve 1s accordingly provided with a rear actuating surface 6 against which pressure fluid may act for pressin the sleeve into engagement with the paw s V. The sleeve z is further rovided with an opposed actuating surface? against which pressure fluid may act for normally retaining said sleeve out of engagement from the pawls V. The ressure fluid utilized for actuating and holdlng the sleeve is conveyed to the actuating surfaces 6 and 7 by supply passages 8 and -9 respectively leading from a valve chamber 10 preferably located in the head block b. v

Disposed within the valve chamber 10 is a valve 11 having end heads 13 and 14 and an intermediate head 15. The heads 13 and 14 are connected to the head 15 by stems 16 and 17 respectively. In the stems 16 and 17 are ports 18 and 19 to afford communication between the valve chamber 10 and recesses 21 and 22 located in the stems 16 and 17' and in the heads associated with said stems.

A closure is provided for the outer end of the valve chamber 10 by a plug 23 threaded into the end of the valve chamber 10. The plug 23 acts as a seat for one end of a spring 24 seated with its other end against the adjacent end of the valve 11 to normally hold said valve in one limiting position. The 0pposite end of the valve 11 constitutes a pressure area 25 against which pressure fluid flowing from the valve chamber 10 through the port 19 to the recess 22 may act for shifting the valve 11 to its other limiting position. Such pressure fluid, as well as that employed for actuating the sleeve 2, is conveyed into the valve chamber 10 by a supply pas sage 26 leading from the throttle valve chamber p to the valve chamber 10 into which it opens at a point between the heads-14 and 15 of the valve. I

In addition to its function of controlling the admission of pressure fluid to the actuating surfaces 6 and 7 the valve 11 also cont-rols the exhaust of such pressure fluid. The head block b is accordingly provided with a passage 27 which leads from a point in the valve chamber 10 and in the same transverse plane as the passage 9 to a point near the outer end of said valve chamber 10. In other words, the outermost end of the passage 27 is so located that when the valve 11 occupies a position to admit pressure fluid to the actuating surface 7 for holding the sleeve free from the pawls, the head 13 of the valve 11 will overlie the outlet opening of the passage 27 to form a closure therefor.

An atmospheric exhaust passage 28 is provided for the valve chamber and is located in the head block b to communicate with the extends through the head block b, the back head Z, the ratchet ring R, the plates H and J and through the cylinder C and the rota-' tion handle q to open into a bore 30 in said rotation handle. The bore '30 is of somewhat larger diameter than the vent 29 and disposed in said bore is a bushing 31 which acts as a guide for the stem 32 of a relief valve 33 which lies within an enlarged recess 34 in the bushing 31 and cooperates with a seat 35 in said bushing to form a closure for the vent 29. A spring 36 acts against the valve to maintain said valve seated upon the seat 35.

The valve 33 is of somewhat smaller diameter than the recess 34 so that, in the open position of the valve, pressure fluid may pass around the edge thereof and through a bore 37 in the bushing 31. In the bushing 31 are ports 38 to communicate the bore 37 with an annular groove 39 in the surface of the bushing 31 and communicating with a passage 40 in the grip portion r.

The stem 32 of the valve 33 extends through the bushing 31 to a point near theouter or free end of the rotation handle 9 and has aflixed thereto a button 41 which is therefore conveniently located with respect to the grip portion 1' so that the valve 33 may be manipulated readily by the same hand wherewith the grip portion 1- is grasped. Preferably the bushing 31 is maintained fixedly in position by a plug 42 threaded into the outer end of the bore 30 and being suitably bored to receive the stem 32 andthe body portion of the button 41.

The operation of the device is as follows: With the throttle valve 0 in the open position, pressure fluid flows into the feeding cylinder f and the valve chambers G and 10. The pressure fluid admitted into the feeding cylinder Wlll act against the piston g and y will move the drilling apparatus toward the work in a well known manner to constantly maintain the percussive element of the drilling apparatus in such position with respect to the working implement as to assure an effective application of the blows of the hammer' piston E to the working implement,

The pressure fluid admitted into the valve chamber G is distributed to the ends of the piston chamber D by the distributing valve F. Upon each admission of fluid into the rear end of the piston chamber D, the piston I3 is actuated forwardly against the working implement and upon the reversal of the valve F pressure fluid is admitted into the front end of the piston chamber D to return the plston.

During such operation of the drilling apparatus, and with the working implement capable of free rotation in the drill hole, the

rifle bar U may rotate freely relatively to the ratchet ring R since during this forward stroke of the piston E, the pawls V will merely pass over the teeth W. The piston E is therefore capable of delivering heavy blows of impact against the working implement.

Upon the return stroke of the piston E the pawls V will be pressed into engagement with the teeth W by the springs X. The piston E will then describe a partial revolution and, bemg suitably interlocked with the working implement, the working implement will also be rotated to change its position in the drill hole for a succeeding blow of the hammer piston.

This operation of the hammer piston and the rotation mechanism may continue indefinitely as long as the working implement remains free to rotate within the drill hole. It happens, however, at times that, due to various causes, the working implement-becomes stuck in the drill hole. At the instant the rotative movement of the drill steel is arrested a thrust or jar of such force is imparted to the rotation handle 1] as to pull the ip portion r out of the operators hand. en the operators grip is released from the rotation handle, the entire drilling mechanism rotates rapidly about the working implement as an axis, and when drilling in narrow and confined quarters it is often diflicult for the operator to quickly withdraw from the range of movement of the rotation handle q. The result invariably is severe injury to the operator.

As may be observed, with the valve 11 in the position illustrated in Figure 1, pressure fluid flows from the throttle valve 0 through the passage 26 and through the valve chamber 10 and the passage 9 into the front end of the chamber There it will act against the actuating surface 7 to hold the sleeve 2 out of engagement from the awls V.

. The valve 11 is retain in this osition by the spring 24 which may be effective for the '5 purpose since, with the valve 33 held in the open position illustrated, the pressure fluid flowing from the valve chamber 10 through the port 19 into the recess 22 escapes through the vent 29 and associated passages to the atmosphere as long as the valve 33 is maintained open by the operator. The valve 11 and the sleeve 2 will then occupyl the positions described and only atmosp eric resare will exist in the rear end of the c am- Iii the event that the drill steel should become wedged within the drill hole to such a degree as to resist the action of the rotation mechanism and should then the grip portion r be -'arred out of the operators hand as is usual y the case, the valve 33 will be instantly closed by the spring 36 acting thereagainst. Communication between the recess 22 and the atmos here will then be cut ofl. The pressure lfl lid thereafter flowing from the valve chamber 10 through the port 19 into the reces 22 will act against the pressure area 25 and will promptly reverse the position of the valve 11.

In the new position of the valve 11, the pressure fluid previously acting against the actuating surface 7 will be exhausted from the front end of the chamber y through the passage 9, around the head 14 of the valve and through the passage 27 into the valve chamber between the heads 13 and 15 whence it flows to the atmosphere through the passage 28. At the same time pressure fluid flows from the valve chamber 10 into the passage 8 into the rear end of the chamber y.

The pressure fluid acting against the actuating surface 6 will press the sleeve 2 forwardly in the direction of the pawls V. The inclined surface 5 on the sleeve 2 will then engage the cam surfaces 8 and will rock the said pawls into a neutral $Sltl0lfl out of engagement from the teeth and will continue to hold the pawls in this position as long as the valve 33 remains closed. The piston E may of course thereafter reciprocate, but its movements are ineffective to change the relative positions of the drilling apparatus and the working implement which it actuates.

released so that it may rotate freely the operator may unseat the valve 33 by pressing the button 41. In this way the pressure fluid acting against the pressure area 25 is exhausted to the atmosphere and the spring 24 may restore the valve 11 to its initial position, thus opening the rear end of the chamber 3 to the atmosphere through the passage 8, the valve chamber 10 and the exhaust passage 28. Simultaneously with the exhaust of pressure fluid from the rear end of the After the working implement is again I chamber 3 pressure fluid will again be admitted into the front end of the chamber through the channels connecting'saidendwi the throttle valve 0. Such pressure fluid will then move the sleeve 2 rearwardly to release the pawls V which may therefore act in the manner required to aflect rotary movement of the piston E.

In ractice, the present invention has been foun to be very eflicient since it eliminates the tendency of the casing elements and the rotation handle 9 to rotate about the working implement whenever the operator releases his grip on the rotation handle. The device acts promptly to prevent such unauthorized rotation and, although the invention is intended more (particularly to avoid the occurrence of arci ents to the operator, it has been found to be also of great value in starting a new drill hole and during which operatlon it is desirable that rotation of the workin implement should temporarily cease until the hole is collared. This advantageous result may be readily brought about by merely allowing the valve-33 to remain closed and the pawls V will then be held in a neutral position. After the drill hole is properly started, the valve 33 may again be opened and'in this way the pawls will be released to perform their customary functions.

I claim:

1. In a safety device, the combination with a rock drill having a hammer piston and rotation mechanism for the iston comprising a rifle bar wherewith said piston is slidabl interlocked, a feeding element for the me drill, a ratchet ring, of pawls carried by the rifle bar to engage the ratchet ring for holding the rifle bar against rotation during one stroke of the piston thus causing the piston to describe a partial revolution, pres- 7 sure actuated trip means for preventing engagement of the pawls with the ratchet ring, and ressure actuated valve means for controlling the supply of pressure fluid to the pressure actuated trip means.

2. In a safety device, the combination with a rock drill having a hammer piston and rotation mechanism for the piston comprising a rifle bar wherewith said piston is slidab y-interlocked, a feeding element for the rock drill, a ratchet ring, of pawls carried by the rifle bar to engage the ratchet ring for holding the rifle bar against rotation during one stroke of the piston thus causing the piston to describe a partial revolution, pressure actuated trip means for preventing engagement of the pawls with the ratchet ring, a pressure actuated valve for controlling the trip means, and a manually operable valve for controlling the said pressure actuated valve.

3. In a safety device, the combination with a rock drill having'a hammer piston .and rotation mechanism for the'piston comprising a rifle bar wherewith said piston is slidab y interlocked, a feeding element for the rock drill, a ratchet ring, of pawls carried by the rifle bar to engage the ratchet ring for holding the rifle bar against rotation during one stroke of the piston thus causing the piston to describe a partial revolution, cam surfaces on'the pawls, pressure fluid actuated trip means to engage the cam surfaces for l holding the awls out of engagement from the ratchet ring, a valve for controlling the supply of pressure fluid to the trip means, and a manually operable valve for controlling the first said valve.

4. In a safety device, the combination with a rock drill having a hammer piston and rotation mechanism for the piston comprising a rifle bar wherewith said piston is slidabl interlocked, a feeding element for the roc drill, a ratchet ring, of pawls carried by the rifle bar to engage the ratchet ring for holding the rifle bar against rotation during one stroke of the piston thus causing the piston to describe a partial revolution, cam surfaces on the pawls, a sleeve in the rock drill having an inclined surface to engage the cam surfaces for holding the pawls out of engagement from the ratchet ring, opposed actuating surfaces on the sleeve, a pressure actuated valve for controlling the supply of pressure fluid to the actuating surfaces, and a manually operable valve for controlling the pressure actuated valve.

5. In a safety device, the combination with a rock drill having a hammer piston and rotation mechanism comprising a rifle bar wherewith said piston is slidably interlocked, a feeding element for the rock drill, a ratchet ring, of pawls carried by the rifle bar to engage the ratchet ring for holding the rifle bar against rotation during one stroke of the piston thus causing the piston to describe a par- -tial revolution, cam surfaces on the pawls, "trip means in the rock drill having an in- -clined surface to cooperate with the cam surfaces for holding the pawls out of engagement from the ratchet ring, a pair of opposed actuating surfaces on the trip means, one of said actuating surfaces being normally subjected to pressure fluid for holding the trip means out of engagement from the pawls and the other actuating surface being selectively subjected to pressure fluid for actuating the trip means into tripping relation with the pawls, and valve means for controlling the supply of pressure fluid to the actuatin surfaces.

6. In a safety device, the com ination with a rock drill having a hammer piston and rotation mechanism comprising a rifle bar wherewith said piston is slidably interlocked, a feeding element for the rock drill, a ratchet ring, of pawls carried by the rifle bar to enga e the ratchet rin for holding the rifle ha against rotation uring one stroke of the piston thus causing the p1ston to describe a vjected to pressure fluid for holding the trip means out of engagement from the pawls and the other actuating surface being selectively subjected to pressure fluid for actuating the trip means into tripping relation with the pawls, a pressure actuated valve for controlling the supply of pressure fluid to the actuating surfaces, and a manually operable valve to control the pressure actuated valve.

7. In a safety device, the combination with a rock drill having a hammer piston and rotation mechanism comprising a rifle bar wherewith said piston is slidably interlocked, a feeding element for the rock drill, a ratchet rlng, of pawls carried by the rifle bar to cooperate with the ratchet ring for holding the, rifle bar against rotation during one stroke of the piston, cam surfaces on the pawls, a sleeve reciprocable in the rock drill and having an inclined surface to engage the cam surfaces for actuating and holding the pawls out of engagement from the ratchet ring, front and rear actuating surfaces on the sleeve, a valve for controlling the supply of pressure fluid to the actuating surfaces and havmg a pressure area, a passage constantly affordmg communication between a source of pressure fluid supply and the pressure area, a spring normally holding the valve in position to admit pressure fluid to the front actuating surface for holding the sleeve out of engagement from the pawls, an atmospheric vent for the pressure area, a relief valve to control the vent and being normally held open to afford communication between the pressure area and the atmosphere, and means to close the relief valve upon release thereof thereby entrapping pressure fluid in the no vent to act against the pressure surface for actuating the first said valve into position to admit pressure fluid to the rear actuating surface to move the sleeve into pawl tripping position. 1

In testimony specification.

15 whereof I have signed this EARL B. LEAR. 

